Subacute thyroiditis is a non-bacterial inflammatory disease associated with viral infection. The main clinical manifestations are enlargement of the thyroid gland with spontaneous pain, tenderness, radiating pain and fever, and is one of the diseases that can be easily misdiagnosed clinically. The etiology of subacute thyroiditis is still unclear, as it is often preceded by a history of upper respiratory tract infections, such as colds, and is thought to be related to viral infections. The onset of the disease is acute, and patients often have sudden onset of untouchable anterior neck pain, which can involve the head, back of the neck, jaw, and behind the ear. Most of them are accompanied by fever, with a body temperature of 37.5℃-39℃. The fever is obvious or aggravated in the afternoon and may subside spontaneously in the morning. The initial phase is accompanied by hyperthyroidism manifestations such as panic, fear of heat and excessive sweating. On examination, the thyroid gland is enlarged, hard or nodular, with obvious tenderness. Laboratory tests include elevated t3, t4, ft3, ft4, increased sedimentation, normal or mildly increased white blood cells. The iodine uptake rate of the thyroid gland is reduced, and the thyroid scan is sparse. If the disease is severe, a few patients develop hypothyroidism in the later stages. The disease can recur many times. Because of the early onset of the disease, there is often a history of upper respiratory tract infections such as colds, followed by fever, anterior neck pain, sore throat, swallowing aggravation, etc. It is easy to misdiagnose as epiglottitis or pharyngitis and give antimicrobial treatment to delay the disease. Therefore, it is important to consider the possibility of subarachnoiditis in patients with fever and pain in the neck and throat and to perform thyroid-related tests. In the process of subthyroiditis, the thyroid tissue is destroyed and a large amount of thyroid hormones are released into the blood, resulting in elevated t3 and t4, which leads to hyperthyroid symptoms such as panic and fear of heat. In the case of subarachnoiditis, t3 and t4 increase while the iodine absorption rate of the thyroid gland decreases, which can be distinguished from hyperthyroidism. In addition, the difference between hyperthyroidism and hyperthyroidism can be made by the urgency of the onset, the duration of the disease, and the presence or absence of proptosis. Hyperthyroidism caused by subarachnoiditis can be relieved after the acute phase of subarachnoiditis and does not require antithyroid drug treatment. In addition, goiter and nodules caused by subthyroiditis may be misdiagnosed as thyroid adenoma, thyroid cancer or nodular goiter and mistakenly treated by surgical removal. There are also a few patients with mild goiter and nodules who are misdiagnosed as cervical spondylosis due to significant neck pain. Treatment: Mild cases are treated with aspirin, indomethacin and other non-steroidal anti-inflammatory drugs, namely porphyrins to control symptoms. Aspirin 0.5 to 1.0g, 2 or 3 times a day, orally, the course of treatment is usually in about 2 weeks. If the symptoms are more severe, prednisone 20-40mg/d can be given orally in divided doses, the symptoms can be relieved quickly, the body temperature will drop, the pain will disappear, and the thyroid nodules will shrink or disappear soon. The dosage can be gradually reduced after 1 to 2 weeks, and the course of treatment is usually 1 to 2 months, but after stopping the drug can be relapsed, and the treatment is still effective again. Those with thyrotoxicosis may be given propranolol to control symptoms. If the iodine uptake rate of the thyroid gland has returned to normal, relapse is usually not repeated after discontinuation of the drug. A small number of patients may develop transient hypothyroidism, and if symptoms are significant, thyroid preparations may be supplemented appropriately. If there is an obvious infection, treatment will be given.